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Frequently Asked Questions
What kind of CAT-5e cable should I be using?
Solid core CAT-5e cable rated at 350 Mhz and terminated in 568a or 568b is the minimum
requirement. For resolutions greater than 1280x1024 or 1080i, Gefen recommends solid
Cat-6 cables.
Why does the CAT5 sender unit have a HDMI connector on the input?
A HDMI connector was used on the input to optimize space on the board by using the
smaller connector. HDMI is electrically equivalent to DVI-D.
I’m getting no video on the screens, what can I check?
First thing to check is make sure that the video CAT5 is linked to the other video CAT5
port and the same with the DDC ports. Test to make sure the units are working with short
CAT-5e cables 15-20 feet. Units shipped starting 12-2005 have the service switches inside
the unit enabled. Please refer to the Service Switch Usage Guide on page 10.
I’m getting no video on the screens using ADC to DVI adapters, what is wrong?
ADC to DVI adapters remove the necessary 5V line that the extenders require on the
input to operate. To enable the 5V you will need to open up the sender unit. Next to each
DVI/HDMI input connector will be a jumper that needs to be shorted to enable 5V to the
input. This should only be enabled when using a ADC to DVI Adapter otherwise damage
to your video card may result.
How can I fi x the fl ickering picture?
Flickering or a Blinking image is the result of a loss of sync between the display and the
source. Try lowering the resolution to see if that helps, if it does, the CAT-5 cables you
are using are unable to handle the bandwidth of the higher resolution and thus you are
losing sync. Try a shielded CAT-5e cable on the Video to reduce interference. You can
also try adjusting the service switches. Usually this is caused from either too much or
too little of a boost. Please refer to the service switch guide on page 10 for the different
combinations.
I can’t seem to get my RS-232 devices to detect and connet, what’s wrong?
The CAT5-7500HD system only extends the Tx and Rx lines of RS232. If you need full
RS232 extension of every line, you will need the standalone RS232 Extender units.
Can I run the CAT-5 cable through a patch bay?
No, the signal will not transmit reliably.